CA1083452A - Solar collector - Google Patents
Solar collectorInfo
- Publication number
- CA1083452A CA1083452A CA278,052A CA278052A CA1083452A CA 1083452 A CA1083452 A CA 1083452A CA 278052 A CA278052 A CA 278052A CA 1083452 A CA1083452 A CA 1083452A
- Authority
- CA
- Canada
- Prior art keywords
- metal
- film
- substrate
- deposited
- thickness
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24S—SOLAR HEAT COLLECTORS; SOLAR HEAT SYSTEMS
- F24S70/00—Details of absorbing elements
- F24S70/20—Details of absorbing elements characterised by absorbing coatings; characterised by surface treatment for increasing absorption
- F24S70/25—Coatings made of metallic material
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24S—SOLAR HEAT COLLECTORS; SOLAR HEAT SYSTEMS
- F24S70/00—Details of absorbing elements
- F24S70/20—Details of absorbing elements characterised by absorbing coatings; characterised by surface treatment for increasing absorption
- F24S70/225—Details of absorbing elements characterised by absorbing coatings; characterised by surface treatment for increasing absorption for spectrally selective absorption
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E10/00—Energy generation through renewable energy sources
- Y02E10/40—Solar thermal energy, e.g. solar towers
Abstract
ABSTRACT OF THE DISCLOSURE
A solar energy collector comprises a glass tube which is coated on its exterior surface with a metal having a relatively low infra-red emittance and then with a composite metal film. The composite metal film comprises a metal-carbide which is deposited on the substrate by a reactive sputtering process.
A solar energy collector comprises a glass tube which is coated on its exterior surface with a metal having a relatively low infra-red emittance and then with a composite metal film. The composite metal film comprises a metal-carbide which is deposited on the substrate by a reactive sputtering process.
Description
8345~, :
This invention relates to a solar energy collector and is more specifically concerned with providing a surface which has a relatively high absorptance of direct or diffuse solar radiation which is incident upon it directly or after reflection by another surface.
Some solar energy collectors currently available operate on the total absorption principle which relies on the provision of a matt black surface capable of absorbing incident energy and transferring it to a fluid medium passed through the collector. In practice, the total absorption surface operates marginally above the temperature of the medium which is to be heated and it inevitably radiates as well as absorbs heat. Attempts are made to reduce the amount of radiated heat as far as is possible, but heat losses through radiation increase with the temperature of operation, so that, in practice, total absorption surfaces are only usable up to about 100C.
Proposals have been made to develop solar energy `
collectors using a "selective surface" which strongly absorbs solar energy but reflects strongly at wavelengths longer than those characteristic of solar radiation. Thus radiation from such a collector is reduced greatly. Collectors in- -corporating such a selective surface are usable at temperatures above 100C for collecting solar heat as their radiation losses ;
:,;:. :
are less than matt black surfaces.
A report on such surfaces appears in publication RI 8167 of the Bureau of Mines Report of Investigations 1976, entitled "Reflectance and Emittance of Spectrally Selective ~ -Titanium and Zirconium Nitrides".
Titanium and zirconium metals are expensive and for this and other reasons involving nitride films, selective ., ~ , .
surface solar collectors have not yet been accepted as commercially viable.
An object of this invention is the provision of improved selective surfaces for collecting solar energy.
In accordance with one aspect of the invention, there is provided a solar energy collector comprising a ;
glass tube which is coated on its exterior surface with a substrate and a composite metal film. The substrate has a thickness of at least 0.05 x 10 6m. and is composed of a metal having a relatively low infra-red emittance. The compo-site metal film comprises a metal-carbide which has a thick-ness between 0.04 x 10 6m. and 0.20 x 10 6m., which is deposited on the substrate by a reactive sputtering process and which, when deposited, has an electrical resistance ;
not greater than 100 K~ per square. ;
In accordance with a second aspect of the inven-tion, there is provided a method of making a solar energy collector of the type above defined.
Technical details of some of the surfaces of the subject of this invention and the techniques employed for producing them are to be found in the Journal of Vacuum Science Technology, Vol. 13, No. 5 Sept./Oct. 1976 (published by the American Vacuum Society) on page 1070 in an artiale by the inventor entitled "Sputtered Metal Carbide Solar Selective Absorbing Surfaces", and on page 1073 of the same ',~: '' publication a second article by the inventor jointly with D. R. McKenzie and B. Window and entitled "The d.c. Sputter Coating of Solar Selective Surfaces onto Tubes".
The preferred metal, from a cost viewpoint, used ~ -in the formation of the film is iron although one can also use `
' .~ :':
,, '',, , D - 2 - ~ `
, . , . ~,.. . .
': , ' ', .. , . .. . ' ~ ~, , , ' : ' ' . ,: ' ' other more expensive metals such as molybdenum, chromium, tungsten, tantalum or titanium or a mixture of them. For example, the sputter electrode may be made of stainless steel to provide iron, chromium and nickel atoms in the film.
The carbon atoms are preferably obtained by employing methane tCH4) or other hydrocarbon as an impurity in an inert gas (e.g., argon) in the reactive sputtering process.
The preferred thickness of the metal carbide film is 0. 09 x 10 6m.
To obtain a uniform film composition on a large substrate it is preferred to use a reactive sputtering process in which the impurity gas is prevented from travelling from one point where, simultaneously, reactive sputtering is taking place to another point where reactive sputtering is also taking place. This may be achieved by using the process described in the aforesaid publication. An advantage of the invention is that stable selective films can be pro-duced from cheap metals such as iron, rather than expensive metals such as molybdenum, tungsten or zirconium. However the invention is also usable with more expensive metals if desired.
The invention operates by using the interference principle. Although the interference principle is well known, the selective surfaces previously suggested have involved metal oxides (such as copper oxide or chromium oxide) which are not particularly stable at high temperatures in vacuum, or relatively expensive refractory metals and metal compounds (such as an "AMA" surface which consists of alternate layers of aluminium oxide and molybdenum oxide).
Thus the selective surfaces so far suggested make the commercial production of high temperature solar ' ' ~ - 3 -.. ' .. . : ' ~L083452 collectors unattractive. The selective surfaces of the invention have the advantage that they can be made using inexpensive metals, such as iron and chromium and are stable at temperatures above 100C and they can be applied by an inexpensive sputtering process. The thickness of the film can be easily controlled by controlling the time for which ~ -sputtering occurs.
The expression "low infra-red emittance" is to be understood in the context of this specification as meaning that the emittance at room temperature is less than 0.10 and -preferably in the range 0.02 and 0.05. Substrates which exhibit such low emittance are, for example, copper, silver, and gold.
The expression "a high absorptance for solar radiation" is to be understood in the context of this speci-fication as meaning that the film absorbs at least 75% and preferably 76% or more of solar radiation which is incident ;
... .. - ~
normal to the surface of the film irrespective of whether such radiation is applied directly or after reflection by another surface such as a cusp or cylinder reflector. ~-~
Single layer metal-carbide films have been -produced routinely on copper substrates by the method of the invention to provide a room temperature emittance of 0.03 and absorptance of 80%.
The invention will now be described in more detail, by way of example, with reference to the accompanying diagrammatic drawing in which:-FIGURE 1 shows a solar energy collector;
FIGURE 2 is a cross-section through an energy collecting tube in the collector; and FIGURE 3 shows a solar heating panel employing such collectors.
~ .' .
.
Figure 1 shows a solar energy collector comprising a cusp reflector 1 surrounding one side of an energy collecting tube 2 through which a fluid medium is continuously passed in the direction of the arrow 3 to extract heat conducted through the wall of the tube and which provides the working medium. In practice, a bank of such collectors would be arranged side by side and the working fluid would be passed through them serially. The aperture of the cusp reflectors is directed towards the sun. A glass envelope 10 encloses the reflector 1.
Figure 2, like Figure 1 is diagrammatic. The light falling on the tube 2 directly and by reflection from the reflector 1 is absorbed by a heat collecting layer 4 which coats a glass cylinder 5 through which the working , :
fluid is passed.
The layer 4 comprises an inner substrate 6 ;~
which is sputtered onto the surface of the glass cylinder 5.
The technique used involves sputtering in a low pressure atmosphere of an inert gas such as argon to build up a copper substrate on the cylinder 5 having a low infra-red emittance as defined. The sputtering is discontinued when the substrate thickness is at least 0.05 x 10 6m and preferably 0.2 x 10 6m thick.
.. . . .
The copper substrate is then coated with a film 7 of iron carbide having a thickness lying between 0.04 x 10 6m and 0.20 x 10 6m, but preferably 0.09 x 10 6m thick. The ~
required thickness of the film and its quality can be obtained `
from the electrical and other parameters of the reactive sputtering process used. It will be understood that the desired electrical resistance is determined by the proportions ~ - 5 -L3 , , 083452 ~ ~
of the metal and carbon atoms in the film. In practiee it has been found that acceptable results are obtained when using the sputtering process described in the Journal of Vacuum Science Technology referred to above and if the metal earbide film has an electrical resistance per square of 10 kilohms to 1 megohm. The deposition process may be controlled to deerease the metal eomponent proportion of the film with increasing thiekness and to inerease the carbon component proportion with inereasing thiekness.
The thiekness of the carbide film is such that the graph of reflectanee (at near normal ineidence of light) exhibits a minimum at wavelengths between 0.80 x 10 6m and 1.0 x 10 6m. This corresponds to a metal carbide film thickness of about 0.09 x 10 6m in practice.
The substrate can be manufactured on a small scale on a plane surface by plaeing a plane eopper dise eleetrode parallel to and spaeed from the surfaee in an inert gas sueh as argon. The surfaee is supported on a seeond plane dise electrode which is at zero electrical potential. The electrode separation from the surface is 17mm and the electrode area is 7.5 x 10 3m2. In these circumstances the following eonditions are suitable for the deposition of the eopper substrate.
Electrode Material Copper Eleetrode Voltage -1200V
Gas Pure Argon Flow Rate As Fast As Possible Gas Pressure 0.2 torr~
Sputtering Time 5 Minutes : . . .
.
33g~5Z
For an electrode area of 7.5 x 10 3m2, the following conditions are suitable for the deposition of the iron carbide film.
Electrode Material Iron (or stainless steel) Electrode Voltage -1200V
Gas 1.6% (by volume) of methane in argon Flow Rate 0.25 cm3s 1 at 1 atmosphere Gas Pressure 0.2 torr. - --Sputtering Time 4 Minutes Film Thickness 0.09 x 10 6m The coating produced under the above conditions has absorptance of 82~ and emittance of 0.03 at room temperature.
For ~oating long glass tubes, the formation of the metal carbide film may be carried out by reactive sputtering using a long metal (e.g. stainl~ss steel) electrode extending parallel to the axis of the tube and spaced about 10 mm from its surface. During sputtering, the tube is slowly rotated about its axis.
Argon and methaneare caused to flow into the -~
sputtering chamber in such a way that the same sputtering conditions are maintained at all points in a plane of sputter-ing through which simultaneous electrical discharge is taking place. This is achieved by arranging for the gas to flow at right angles to the plane from a perforated inlet pipe to a ~-perforated outlet pipe both of which extend parallel to the electrode and which lie, respectively, on opposite sides of the sputtering plane. By carrying out the sputtering under these conditions the film deposited on the tube is of uniform thickness along its length.
The total film thickness is determined by the time during which sputtering occurs and the quality of the _ 7 _ .~ . . . . . . . . . .
:-- 108345Z
film by monitoring the electrical resistance of the film.
The formation of the copper substrate may be carried out by sputtering using a copper electrode extending parallel to the axis of the tube and using pure argon in the gas flow.
After formation of the copper substrate 6 and the metal carbide film 7, the collector tube so formed is sheathed in the permanently sealed vacuum envelope 10, which is made of baked pyrex or soda glass, together with the reflector 1.
The reflector 1 is not, incidentally, essential.
The working fluid may comprise oil or another fluid which can be passed into a collector through a conduit extending into the collecting tube. The fluid then passes along the annular space between the conduit and the tube and out of the tube.
A number of such tubes are mounted side by side to form a heating array of a solar heating panel 20 as shown in -Figure 3, which is mounted facing the sun and has the tubes hydraulically connected in series or in parallel in a closed circuit 21 containing a pump 22 and a heat exchanger 23.
~ .
This invention relates to a solar energy collector and is more specifically concerned with providing a surface which has a relatively high absorptance of direct or diffuse solar radiation which is incident upon it directly or after reflection by another surface.
Some solar energy collectors currently available operate on the total absorption principle which relies on the provision of a matt black surface capable of absorbing incident energy and transferring it to a fluid medium passed through the collector. In practice, the total absorption surface operates marginally above the temperature of the medium which is to be heated and it inevitably radiates as well as absorbs heat. Attempts are made to reduce the amount of radiated heat as far as is possible, but heat losses through radiation increase with the temperature of operation, so that, in practice, total absorption surfaces are only usable up to about 100C.
Proposals have been made to develop solar energy `
collectors using a "selective surface" which strongly absorbs solar energy but reflects strongly at wavelengths longer than those characteristic of solar radiation. Thus radiation from such a collector is reduced greatly. Collectors in- -corporating such a selective surface are usable at temperatures above 100C for collecting solar heat as their radiation losses ;
:,;:. :
are less than matt black surfaces.
A report on such surfaces appears in publication RI 8167 of the Bureau of Mines Report of Investigations 1976, entitled "Reflectance and Emittance of Spectrally Selective ~ -Titanium and Zirconium Nitrides".
Titanium and zirconium metals are expensive and for this and other reasons involving nitride films, selective ., ~ , .
surface solar collectors have not yet been accepted as commercially viable.
An object of this invention is the provision of improved selective surfaces for collecting solar energy.
In accordance with one aspect of the invention, there is provided a solar energy collector comprising a ;
glass tube which is coated on its exterior surface with a substrate and a composite metal film. The substrate has a thickness of at least 0.05 x 10 6m. and is composed of a metal having a relatively low infra-red emittance. The compo-site metal film comprises a metal-carbide which has a thick-ness between 0.04 x 10 6m. and 0.20 x 10 6m., which is deposited on the substrate by a reactive sputtering process and which, when deposited, has an electrical resistance ;
not greater than 100 K~ per square. ;
In accordance with a second aspect of the inven-tion, there is provided a method of making a solar energy collector of the type above defined.
Technical details of some of the surfaces of the subject of this invention and the techniques employed for producing them are to be found in the Journal of Vacuum Science Technology, Vol. 13, No. 5 Sept./Oct. 1976 (published by the American Vacuum Society) on page 1070 in an artiale by the inventor entitled "Sputtered Metal Carbide Solar Selective Absorbing Surfaces", and on page 1073 of the same ',~: '' publication a second article by the inventor jointly with D. R. McKenzie and B. Window and entitled "The d.c. Sputter Coating of Solar Selective Surfaces onto Tubes".
The preferred metal, from a cost viewpoint, used ~ -in the formation of the film is iron although one can also use `
' .~ :':
,, '',, , D - 2 - ~ `
, . , . ~,.. . .
': , ' ', .. , . .. . ' ~ ~, , , ' : ' ' . ,: ' ' other more expensive metals such as molybdenum, chromium, tungsten, tantalum or titanium or a mixture of them. For example, the sputter electrode may be made of stainless steel to provide iron, chromium and nickel atoms in the film.
The carbon atoms are preferably obtained by employing methane tCH4) or other hydrocarbon as an impurity in an inert gas (e.g., argon) in the reactive sputtering process.
The preferred thickness of the metal carbide film is 0. 09 x 10 6m.
To obtain a uniform film composition on a large substrate it is preferred to use a reactive sputtering process in which the impurity gas is prevented from travelling from one point where, simultaneously, reactive sputtering is taking place to another point where reactive sputtering is also taking place. This may be achieved by using the process described in the aforesaid publication. An advantage of the invention is that stable selective films can be pro-duced from cheap metals such as iron, rather than expensive metals such as molybdenum, tungsten or zirconium. However the invention is also usable with more expensive metals if desired.
The invention operates by using the interference principle. Although the interference principle is well known, the selective surfaces previously suggested have involved metal oxides (such as copper oxide or chromium oxide) which are not particularly stable at high temperatures in vacuum, or relatively expensive refractory metals and metal compounds (such as an "AMA" surface which consists of alternate layers of aluminium oxide and molybdenum oxide).
Thus the selective surfaces so far suggested make the commercial production of high temperature solar ' ' ~ - 3 -.. ' .. . : ' ~L083452 collectors unattractive. The selective surfaces of the invention have the advantage that they can be made using inexpensive metals, such as iron and chromium and are stable at temperatures above 100C and they can be applied by an inexpensive sputtering process. The thickness of the film can be easily controlled by controlling the time for which ~ -sputtering occurs.
The expression "low infra-red emittance" is to be understood in the context of this specification as meaning that the emittance at room temperature is less than 0.10 and -preferably in the range 0.02 and 0.05. Substrates which exhibit such low emittance are, for example, copper, silver, and gold.
The expression "a high absorptance for solar radiation" is to be understood in the context of this speci-fication as meaning that the film absorbs at least 75% and preferably 76% or more of solar radiation which is incident ;
... .. - ~
normal to the surface of the film irrespective of whether such radiation is applied directly or after reflection by another surface such as a cusp or cylinder reflector. ~-~
Single layer metal-carbide films have been -produced routinely on copper substrates by the method of the invention to provide a room temperature emittance of 0.03 and absorptance of 80%.
The invention will now be described in more detail, by way of example, with reference to the accompanying diagrammatic drawing in which:-FIGURE 1 shows a solar energy collector;
FIGURE 2 is a cross-section through an energy collecting tube in the collector; and FIGURE 3 shows a solar heating panel employing such collectors.
~ .' .
.
Figure 1 shows a solar energy collector comprising a cusp reflector 1 surrounding one side of an energy collecting tube 2 through which a fluid medium is continuously passed in the direction of the arrow 3 to extract heat conducted through the wall of the tube and which provides the working medium. In practice, a bank of such collectors would be arranged side by side and the working fluid would be passed through them serially. The aperture of the cusp reflectors is directed towards the sun. A glass envelope 10 encloses the reflector 1.
Figure 2, like Figure 1 is diagrammatic. The light falling on the tube 2 directly and by reflection from the reflector 1 is absorbed by a heat collecting layer 4 which coats a glass cylinder 5 through which the working , :
fluid is passed.
The layer 4 comprises an inner substrate 6 ;~
which is sputtered onto the surface of the glass cylinder 5.
The technique used involves sputtering in a low pressure atmosphere of an inert gas such as argon to build up a copper substrate on the cylinder 5 having a low infra-red emittance as defined. The sputtering is discontinued when the substrate thickness is at least 0.05 x 10 6m and preferably 0.2 x 10 6m thick.
.. . . .
The copper substrate is then coated with a film 7 of iron carbide having a thickness lying between 0.04 x 10 6m and 0.20 x 10 6m, but preferably 0.09 x 10 6m thick. The ~
required thickness of the film and its quality can be obtained `
from the electrical and other parameters of the reactive sputtering process used. It will be understood that the desired electrical resistance is determined by the proportions ~ - 5 -L3 , , 083452 ~ ~
of the metal and carbon atoms in the film. In practiee it has been found that acceptable results are obtained when using the sputtering process described in the Journal of Vacuum Science Technology referred to above and if the metal earbide film has an electrical resistance per square of 10 kilohms to 1 megohm. The deposition process may be controlled to deerease the metal eomponent proportion of the film with increasing thiekness and to inerease the carbon component proportion with inereasing thiekness.
The thiekness of the carbide film is such that the graph of reflectanee (at near normal ineidence of light) exhibits a minimum at wavelengths between 0.80 x 10 6m and 1.0 x 10 6m. This corresponds to a metal carbide film thickness of about 0.09 x 10 6m in practice.
The substrate can be manufactured on a small scale on a plane surface by plaeing a plane eopper dise eleetrode parallel to and spaeed from the surfaee in an inert gas sueh as argon. The surfaee is supported on a seeond plane dise electrode which is at zero electrical potential. The electrode separation from the surface is 17mm and the electrode area is 7.5 x 10 3m2. In these circumstances the following eonditions are suitable for the deposition of the eopper substrate.
Electrode Material Copper Eleetrode Voltage -1200V
Gas Pure Argon Flow Rate As Fast As Possible Gas Pressure 0.2 torr~
Sputtering Time 5 Minutes : . . .
.
33g~5Z
For an electrode area of 7.5 x 10 3m2, the following conditions are suitable for the deposition of the iron carbide film.
Electrode Material Iron (or stainless steel) Electrode Voltage -1200V
Gas 1.6% (by volume) of methane in argon Flow Rate 0.25 cm3s 1 at 1 atmosphere Gas Pressure 0.2 torr. - --Sputtering Time 4 Minutes Film Thickness 0.09 x 10 6m The coating produced under the above conditions has absorptance of 82~ and emittance of 0.03 at room temperature.
For ~oating long glass tubes, the formation of the metal carbide film may be carried out by reactive sputtering using a long metal (e.g. stainl~ss steel) electrode extending parallel to the axis of the tube and spaced about 10 mm from its surface. During sputtering, the tube is slowly rotated about its axis.
Argon and methaneare caused to flow into the -~
sputtering chamber in such a way that the same sputtering conditions are maintained at all points in a plane of sputter-ing through which simultaneous electrical discharge is taking place. This is achieved by arranging for the gas to flow at right angles to the plane from a perforated inlet pipe to a ~-perforated outlet pipe both of which extend parallel to the electrode and which lie, respectively, on opposite sides of the sputtering plane. By carrying out the sputtering under these conditions the film deposited on the tube is of uniform thickness along its length.
The total film thickness is determined by the time during which sputtering occurs and the quality of the _ 7 _ .~ . . . . . . . . . .
:-- 108345Z
film by monitoring the electrical resistance of the film.
The formation of the copper substrate may be carried out by sputtering using a copper electrode extending parallel to the axis of the tube and using pure argon in the gas flow.
After formation of the copper substrate 6 and the metal carbide film 7, the collector tube so formed is sheathed in the permanently sealed vacuum envelope 10, which is made of baked pyrex or soda glass, together with the reflector 1.
The reflector 1 is not, incidentally, essential.
The working fluid may comprise oil or another fluid which can be passed into a collector through a conduit extending into the collecting tube. The fluid then passes along the annular space between the conduit and the tube and out of the tube.
A number of such tubes are mounted side by side to form a heating array of a solar heating panel 20 as shown in -Figure 3, which is mounted facing the sun and has the tubes hydraulically connected in series or in parallel in a closed circuit 21 containing a pump 22 and a heat exchanger 23.
~ .
Claims (4)
1. A solar energy collector comprising a glass tube which is coated on its exterior surface with a substrate and a composite metal film; the substrate having a thickness of at least 0.05 x 10-6m. and being composed of a metal having a low infra-red emittance, and the composite metal film com-prising a metal-carbide which has a thickness between 0.04 x 10-6m. and 0.20 x 10-6m., which is deposited on the substrate by a reactive sputtering process and which, when deposited, has an electrical resistance not greater than 100 K .OMEGA. per square.
2. A solar energy collector as claimed in claim 1, wherein the composite metal film comprises atoms of iron, chromium, nickel and carbon which are deposited to form a film thickness of about 0.10 x 10-6m.
3. A solar energy collector as claimed in claim 1 or claim 2 wherein the substrate comprises copper which is deposited on the glass tube surface by a sputtering process.
4. A method of making a solar energy collector comprising the steps of depositing onto the external surface of a glass tube to a thickness of not less than 0.05 x 10-6m.
a substrate composed of a metal having a low infra-red emittance, and depositing onto the substrate by a reactive sputtering process a metal carbide film, the metal carbide film being deposited to a thickness falling within the range 0.04 x 10-6m. to 0.20 x 10-6m. and the relative proportions of the metal and carbon atoms being controlled during the depositing process to provide for an electrical resistance, when the metal carbide film is deposited, which is not greater than 100 K .OMEGA. per square.
a substrate composed of a metal having a low infra-red emittance, and depositing onto the substrate by a reactive sputtering process a metal carbide film, the metal carbide film being deposited to a thickness falling within the range 0.04 x 10-6m. to 0.20 x 10-6m. and the relative proportions of the metal and carbon atoms being controlled during the depositing process to provide for an electrical resistance, when the metal carbide film is deposited, which is not greater than 100 K .OMEGA. per square.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| AUPC6229 | 1976-06-10 | ||
| AUPC622976 | 1976-06-10 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1083452A true CA1083452A (en) | 1980-08-12 |
Family
ID=3766678
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA278,052A Expired CA1083452A (en) | 1976-06-10 | 1977-05-10 | Solar collector |
Country Status (11)
| Country | Link |
|---|---|
| JP (1) | JPS52150834A (en) |
| CA (1) | CA1083452A (en) |
| CH (1) | CH624755A5 (en) |
| DE (1) | DE2725914A1 (en) |
| ES (1) | ES459670A1 (en) |
| FR (1) | FR2354521A1 (en) |
| GB (1) | GB1558440A (en) |
| IL (1) | IL52213A (en) |
| IT (1) | IT1083135B (en) |
| NL (1) | NL180124C (en) |
| SE (1) | SE422783B (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8182929B2 (en) | 2005-03-03 | 2012-05-22 | The University Of Sydney | Solar absorptive material for a solar selective surface coating |
Families Citing this family (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| AU5318779A (en) * | 1979-01-26 | 1981-07-02 | Exxon Research And Engineering Company | Solar absorber |
| FR2524618B1 (en) * | 1982-03-31 | 1987-11-20 | Commissariat Energie Atomique | COATING FOR PHOTOTHERMAL CONVERSION |
| DE3219989A1 (en) * | 1982-05-27 | 1983-12-01 | Maschf Augsburg Nuernberg Ag | SELECTIVE ABSORBING LAYER FOR SOLAR COLLECTORS AND METHOD FOR THE PRODUCTION THEREOF |
| GB2147408A (en) * | 1983-10-04 | 1985-05-09 | Dimos Maglaras | Solar water heater |
| US4777068A (en) * | 1984-08-10 | 1988-10-11 | Canon Kabushiki Kaisha | Optical recording medium |
| GB8827541D0 (en) * | 1988-11-25 | 1988-12-29 | Atomic Energy Authority Uk | Multilayer coatings |
| DE19515647A1 (en) * | 1995-04-28 | 1996-10-31 | Lazarov Miladin Dr | Economical radiation-selective absorber with good optical quality |
| AU2006220251B2 (en) * | 2005-03-03 | 2011-11-17 | The University Of Sydney | A solar absorptive material for a solar selective surface coating |
| DE102009048672A1 (en) * | 2009-09-30 | 2011-03-31 | Siemens Aktiengesellschaft | Central tube for a linear concentrating solar thermal power plant with absorber layer and method for applying this absorber layer |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3173801A (en) * | 1961-05-26 | 1965-03-16 | Thompson Ramo Wooldridge Inc | Electromagnetic radiation energy arrangement |
| US3287243A (en) * | 1965-03-29 | 1966-11-22 | Bell Telephone Labor Inc | Deposition of insulating films by cathode sputtering in an rf-supported discharge |
| DE2508339A1 (en) * | 1974-05-06 | 1975-11-20 | Arnold Dr Keller | Hollow cylindrical type solar cell - in which complicated assembly of lenses and mirrors is eliminated |
-
1977
- 1977-05-10 CH CH580477A patent/CH624755A5/en not_active IP Right Cessation
- 1977-05-10 CA CA278,052A patent/CA1083452A/en not_active Expired
- 1977-05-17 NL NLAANVRAGE7705467,A patent/NL180124C/en not_active IP Right Cessation
- 1977-06-01 FR FR7716655A patent/FR2354521A1/en active Granted
- 1977-06-01 IL IL52213A patent/IL52213A/en unknown
- 1977-06-03 GB GB23792/77A patent/GB1558440A/en not_active Expired
- 1977-06-06 IT IT7768300A patent/IT1083135B/en active
- 1977-06-07 JP JP6722577A patent/JPS52150834A/en active Granted
- 1977-06-08 DE DE19772725914 patent/DE2725914A1/en active Granted
- 1977-06-08 SE SE7706648A patent/SE422783B/en not_active IP Right Cessation
- 1977-06-10 ES ES459670A patent/ES459670A1/en not_active Expired
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8182929B2 (en) | 2005-03-03 | 2012-05-22 | The University Of Sydney | Solar absorptive material for a solar selective surface coating |
Also Published As
| Publication number | Publication date |
|---|---|
| IL52213A0 (en) | 1977-08-31 |
| FR2354521B1 (en) | 1985-02-15 |
| DE2725914A1 (en) | 1977-12-22 |
| NL180124C (en) | 1987-01-02 |
| SE7706648L (en) | 1977-12-11 |
| ES459670A1 (en) | 1978-11-16 |
| IL52213A (en) | 1979-10-31 |
| DE2725914C2 (en) | 1987-02-19 |
| SE422783B (en) | 1982-03-29 |
| FR2354521A1 (en) | 1978-01-06 |
| NL7705467A (en) | 1977-12-13 |
| NL180124B (en) | 1986-08-01 |
| JPS5545815B2 (en) | 1980-11-19 |
| IT1083135B (en) | 1985-05-21 |
| JPS52150834A (en) | 1977-12-14 |
| CH624755A5 (en) | 1981-08-14 |
| GB1558440A (en) | 1980-01-03 |
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